On Thu, Mar 23, 2023 at 5:43 PM <rsbecker@xxxxxxxxxxxxx> wrote: > > On Thursday, March 23, 2023 7:35 PM, Felipe Contreras wrote: > >On Thu, Mar 23, 2023 at 5:30 PM <rsbecker@xxxxxxxxxxxxx> wrote: > >> > >> On Thursday, March 23, 2023 7:22 PM, Felipe Contreras wrote: > >> >On Sat, Feb 18, 2023 at 5:12 AM Phillip Wood <phillip.wood123@xxxxxxxxx> > >wrote: > >> >> > >> >> On 18/02/2023 01:59, demerphq wrote: > >> >> > On Sat, 18 Feb 2023 at 00:24, Junio C Hamano <gitster@xxxxxxxxx> wrote: > >> >> >> > >> >> >> Emily Shaffer <nasamuffin@xxxxxxxxxx> writes: > >> >> >> > >> >> >>> Basically, if this effort turns out not to be fruitful as a > >> >> >>> whole, I'd like for us to still have left a positive impact on the codebase. > >> >> >>> ... > >> >> >>> So what's next? Naturally, I'm looking forward to a spirited > >> >> >>> discussion about this topic - I'd like to know which concerns > >> >> >>> haven't been addressed and figure out whether we can find a way > >> >> >>> around them, and generally build awareness of this effort with the > >community. > >> >> >> > >> >> >> On of the gravest concerns is that the devil is in the details. > >> >> >> > >> >> >> For example, "die() is inconvenient to callers, let's propagate > >> >> >> errors up the callchain" is an easy thing to say, but it would > >> >> >> take much more than "let's propagate errors up" to libify > >> >> >> something like > >> >> >> check_connected() to do the same thing without spawning a > >> >> >> separate process that is expected to exit with failure. > >> >> > > >> >> > > >> >> > What does "propagate errors up the callchain" mean? One > >> >> > interpretation I can think of seems quite horrible, but another > >> >> > seems quite doable and reasonable and likely not even very > >> >> > invasive of the existing code: > >> >> > > >> >> > You can use setjmp/longjmp to implement a form of "try", so that > >> >> > errors dont have to be *explicitly* returned *in* the call chain. > >> >> > And you could probably do so without changing very much of the > >> >> > existing code at all, and maintain a high level of conceptual > >> >> > alignment with the current code strategy. > >> >> > >> >> Using setjmp/longjmp is an interesting suggestion, I think lua does > >> >> something similar to what you describe for perl. However I think > >> >> both of those use a allocator with garbage collection. I worry that > >> >> using longjmp in git would be more invasive (or result in more > >> >> memory leaks) as we'd need to to guard each allocation with some > >> >> code to clean it up and then propagate the error. That means we're > >> >> back to manually propagating errors up the call chain in many cases. > >> > > >> >We could just use talloc [1]. > >> > >> talloc is not portable. > > > >What makes you say that? > > talloc is not part of a POSIX standard I could find. It's a library, like: z, ssl, curl, pcre2-8, etc. Libraries can be compiled on different platforms. -- Felipe Contreras
